Dear Sylvie Guillem

Some friendly advice for the Royal Ballet's principal guest artist - who won't have her picture taken

I love this picture of you. You look cool, Parisian, ravishingly beautiful and not a bit like a ballerina. It encapsulates the 23-year- old Nureyev protege with the hennaed bob and difficult reputation. It's a cracking shot and if I had one as good of myself I, too, would have a 10 by 8 enlargement on the piano. But yours is seven years old.

We all have our favourite snapshots. I know people who've been using the same ID on their bus pass since they were 18. This kind of vanity is hardly unusual in the arts: theatre programmes abound with cheesecake headshots of actors glimpsed through Vaseline-smeared lenses in 1978, but at least they have the grace to have fresh photographs taken for each round of publicity. Their press offices bully them into it.

You, meanwhile, do your own PR. The danger with clinging to an outmoded version of yourself is that one day you may wake to find you no longer bear any resemblance to the girl in the picture - but by then, like Julie Burchill, you will be doomed to use the same headshot for ever.

I know it's not entirely true to say you refuse to have your photograph taken: you consented to yesterday's ensemble shots at the Royal Ballet photocall for your new piece Firstext and will agree to any reasonable photographic request. Provided you OK the photographer. And provided it's only used in connection with that specific ballet. And provided you get full approval of the end result (Marilyn Monroe was known to insist on this. Her famous last sitting with Bert Stern was allowed on the understanding that she could go over the contacts armed with a Lupe and a hairpin). What you don't want is a load of pictures accumulating in a file somewhere being dug out and used every time someone writes about you - which leaves us with this glamour shot of you at 16.

It's hard to blame you for keeping a low profile. You have suffered many times at the hands of Fleet Street picture editors convinced that one brunette in a tutu is much like another. Your notoriously camera-shy stance is part perfectionism, part indifference. Your name on the programme is enough to fill houses: you're a star, you don't need the publicity. But what about posterity?

No authenticated cine film exists of Isadora Duncan's rhapsodies but we can create some sense of her beauty and personal magnetism from the vast archive of stills. Portraits, news photographs, album snaps and artistic studies combine to conjure the ghost of a dancer that galvanised a generation. If you were to give up ballet tomorrow we would be left with a few South Bank Shows and a handful of artfully posed, vetted studio studies by your authorised portraitist Gilles Tapie - an able lensman but one who seems strangely reluctant to snap anyone who isn't standing still (a handicap for a ballet photographer). From photographs, we know more about Duncan or Pavlova than about you.

We're all vain. No normal person likes to see a photograph that doesn't do them justice. But you're not a normal person. You're a star. Behave like one. And smile.